Sizing device for effecting sizing over a wide range

ABSTRACT

A SIZING DEVICE FOR GRINDERS OR THE LIKE WHICH USES A FEELER OR FEELERS MOUNTED ON A SIZING HEAD FOR CONTACTING A WORKPIECE, AND A DISPLACEMENT DETECTOR FOR SENSING THE DISPLACEMENT OF THE FEELER OR FEELERS CAUSED BY A CHANGE IN THE OUTER CIRCUMFERENTIAL DIMENSION OF THE WORKPIECE SO AS TO CONTROL THE FEED OF WHEEL SLIDE. THE DISPLACEMENT DETECTOR IS MOVED IN ACCORDANCE WITH NUMERICAL DATA PREVIOUSLY STORED, SO THAT THE POINT OF GENERATION OF A SIZING SIGNAL BY THE DISPLACEMENT DETECTOR CAN BE MOVED. THE SIZING DEVICE MEASURES THE DIAMETER OF A WORKPIECE ACCURATELY AND OVER A WIDE RANGE BY ELIMINATING MASTER SETING.

March 9, 1971 H|ROAK| ASANO ET AL 3,568,372

SIZING DEVICE FOR EFFECTING SIZING OVER A WIDE RANGE Filed Dec. 4, 19683 Sheets-Sheet l Q ID N I N m a m m (3 m q lllgllll "N m o rq N h N 53 I92 .l I q.

co U1 93 I o I N :1 ar' March 9, 1971 HIROAKI AsANo' 3,563,372

SIZING DEVICE FOR EFFECTINC' SIZING OVER A WIDE RANGE Filed Dec. 4-,1968 '3 SheetsSheet 2 March 9, 1971 HIROAK] ASANO ET AL 3,568,372

SIZING DEVICE FOR EFFECTING SIZING OVER A WIDE RANGE Filed Dec. 4, 19683 Sheets-Sheet 3 5 Z LIJ U +42 l 1% g 5 O l 939mm LL B m :2 m g .Lfld m00 United States Patent O 3,568,372 SIZING DEVICE FOR EFFECTING SIZINGOVER A WIDE RANGE Hiroaki Asano and Hideo Nishimura, Kariya-shi, Japan,

assignors to Toyoda Koki Kabushiki Kaisha, Kariya- Shi, Japan Filed Dec.4, 1968, Ser. No. 781,105 Claims priority, application Japan, Dec. 15,1967,

42/80,368; Nov. 4, 1968, 43/80,485

Int. Cl. B24b 49/04 US. Cl. 51165 12 Claims ABSTRACT OF THE DISCLOSURE Asizing device for grinders or the like which uses a feeler or feelersmounted on a sizing head for contacting a workpiece, and a displacementdetector for sensing the displacement of the feeler or feelers caused bya change in the outer circumferential dimension of the workpiece so asto control the feed of wheel slide. The displacement detector is movedin accordance with numerical data previously stored, so that the pointof generation of a sizing signal by the displacement detector can bemoved. The sizing device measures the diameter of a workpiece accuratelyand over a wide range by eliminating master setting.

BACKGROUND OF THE INVENTION The present invention relates to sizingdevices in general, and in particular the invention is concerned with asizing device for grinders and the like which permits control of thefeed motion of a wheel slide by measuring the diameter of a workpiece.

Sizing devices of the prior art can effect very high precision sizing.However, as their range of sizing is determined, a so-called mastersetting is essential for effecting adjustments of the position offeelers or adjustments of the operation point of a sizing signal inconformity with the diameter of the workpiece. The sizing device inwhich a master setting is once effected cannot handle workpieces ofother dimensional values than a predetermined value set for a particularworkpiece. Therefore, it has hitherto been required to effect mastersetting of a sizing device each time different workpieces are handled orto use a plurality of sizing devices which are each set to handle aworkpiece of a particular diameter. Effecting master setting is a verycomplicated process involving a certain degree of skill and a prolongedoperation time. Moreover, it is required to prepare masters of variousdimensions previously finished to have predetermined values. Thus, thepresent practice is to employ a sizing device only in cases where alarge number of workpieces are ground to the same dimension.

SUMMARY OF THE INVENTION According to the present invention, there isprovided a sizing device for grinders or the like which comprises feelermeans mounted on a sizing head pivotally supported by a suspensionspring mounted on a main supporting structure for contacting the outercircumference of a workpiece supported by a pair of fixed jaws, saidfeeler means being adapted to move as the diameter of said workpiecevaries, displacement detecting means for sensice ing the relativedisplacement of said feeler means, an output circuit for generating anelectric switch signal at the point of operation of said displacementdetecting means, movable feed control means responding to a given sizinginstruction for moving said feeler means and said displacement detectingmeans with respect to the work piece, driving means connected to saidfeed control means, and control means for operating said driving means.

The invention also provides a sizing device for grinders or the likewhich comprises feeler means including a pair of feelers mounted on asizing head for movement in ac cordance with the value of a generatedsizing signal, said pair of feelers contacting a workpiece at two pointson said workpiece diametrically opposed to each other and one of saidpair of feelers being capable of moving pivotally, and displacementdetecting means mounted on said pivotally supported feeler andresponding to a change in the outer diameter of the workpiece.

The invention also provides a sizing device for grinders or the likewhich comprises control means for operating feeler means, said controlmeans comprising a tape reader and numerical command means, saidnumerical command means being operated by instructions from said tapereader for effecting control of ad riving mechanism of the feeler means.

OBJECTS OF THE INVENTION A principal object of the present invention isto provide a sizing device adapted for elfecting sizing over a widerange at high precision by accommodating changes in the outer diameterof a workpiece.

Another object of the invention is to provide a sizing device adaptedfor effecting sizing over a wide range which relies on numericalcontrol.

Another object of the invention is to provide a sizing device foreffecting sizing over a wide range in which predetermined amounts ofrelative displacements of a feeler or feelers in contact with aworkpiece and a displacement detector for sensing a relativedisplacement of said feeler or feelers are set by numerical datapreviously stored so that the point of generation of a sizing signal ofthe displacement detector can be moved.

Still another object of the invention is to provide a sizing deviceadapted for effecting sizing over a wide range which can accommodatevariations over a wider range in the outer diameter of a workpiece to besized than sizing device of the jaw type, once a master setting iseffected.

A further object of this invention is to provide a sizing device adaptedfor effecting sizing over a wide range including supporting and guidingmeans which permits sizing accurately and with high precision.

A still further object of the invention is to provide a sizing deviceadapted for effecting sizing over a wide range in which protectivecovers are mounted between upper and lower jaws of a sizing head and apair of supporters and between said supporters themselves so that thesliding portions of said supporters can be protected by said protectivecovers against coolant or grinding wheel particles during grindingoperations.

Additional objects and advantages of the invention will become apparentfrom consideration of the description set forth below when considered inconjunction with the accompanying drawings.

3 BRIEF EXPLANATION OF THE DRAWINGS FIG. 1 is a sectional view of afirst embodiment of the sizing device according to this invention;

FIG. 2 is a longitudinal sectional view of a second em 'bodiment of thesizing device according to this invention;

FIG. 3 is a front view of the second embodiment shown in FIG. 2, withcertain parts being broken away;

FIG. 4 is a longitudinal sectional view of a third em-- bodiment of thesizing device according to this invention;

FIG. 5 is a sectional view taken along the line VV of FIG. 4 and seen inthe direction of arrows;

FIG. 6 is a sectional view taken along the line VI-VI of FIG. 4 and seenin the direction of arrows;

FIG. 7 is an end view of the portion taken along the line VII-VII ofFIG. 4 and seen in the direction of arrows;

FIG. 8 is a block diagram of a control circuit used when the deviceaccording to this invention is applied to a grinder of the numericalcontrol type; and

FIGS. 9a and 9b show output characteristics of a displacement detector.

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of thisinvention will now be explained with reference to FIG. 1. A pair offixed jaws 2 land 2 are mounted on vertically aligned surfaces 1a and Inat the front end of a sizing head 1. The positions in which said fixedjaws are mounted can be adjusted and varied by conventional positionadjusting means. A movable feeler 3 is supported concentrically withsupporter means 4 which mounts therein a displacement detector A. Thesupporter means '4 is supported by the sizing head 1 for axial slidingmotion and restrained against rotation by a key 5. A rod 6 formed with afine threaded portion thereon projects rearwardly from the rear end ofthe supporter means 4 for threadable engagement with a diiferential nut7. The differential nut 7 has an externally threaded portion which is inthreadable engagement with the sizing head 1. Rotation of the nut 7 bymeans subsequently to be described results in displacement of thesupporter means 4 by an amount corresponding to a difference in pitchbetween the internally threaded portion and the externally threadedportion of the nut 7. A spring 8 for eliminating backlash of the nut ismounted between the supporter means 4 and the sizing head 1. Asuspension spring 10 floatingly mounts the sizing head 1 on a mainsupporter 9. A transducer G is mounted on the suspension spring 10 fordetecting the deflection of the spring. A stop 11 for restraining thesizing head 1 against rotation is received in a recess 12. Firmlysecured to the main supporter 9 is a pulse motor 13 which has a rotaryshaft 14 connected to the differential nut 7 through joint means 15, 16,and 18. Said joint member 18 has one end which is spherical in shape forfloatingly accommodating the sizing head 1. A drive pin 17 is fixed tothe joint member 18. A pilot bar 19 and a piston rod 20 connected to apis ton 21 are fixed at one end thereof to the main supporter 9 which ismoved horizontally in reciprocating motion by the pressing force of aquantity of fluid supplied under pressure to a cylinder 22 from a fluidsource 27. The foremost advance position of the main supporter 9 iscontrolled by an output signal of the transducer G mounted on thesuspension spring 10. Upon occurrence of a predetermined amount ofdeflection in the suspension spring 10, the output voltage due to thechange of resistences' workpiece W, because a change in the outerdiameter of the workpiece does not cause deflection of the suspensionspring 10 over and above a predetermined amount. The displacementdetector A in the present invention may be any device available, such asan electric micrometer or pneumatic micrometer. The displacementdetector used in the present embodiment is a differential transformer inwhich a bobbin 23 having a primary coil and a secondary coil woundthereon and a movable iron core 24 are mounted concentrically, saidmovable iron core 24 being connected to the aforementioned movablefeeler 3 which is urged forwardly by a spring 25 for providing contactpressure at all times.

In a sizing device of the jaw type described above, the point of contactbetween the movable feeler 3 and the workpiece W is displaced by anamount proportional to a change in the outer diameter of the workpiece.The amount of displacement is equal to the amount of change Ar in theradius of the workpiece when the angle a defined by the pair of fixedjaws 2 and 2 is '60 degrees. Thus, when the'radius R is increased, thepoint of contact S is moved forwardly (toward the center of axis of theworkpiece); when the radius is reduced, the point of contact is movedrearwardly.

To effect the initial master setting, the supporter means 4 ispositioned at a predetermined position and a Schmitt circuit or the likeresponsive to the output of the displacement detector A is adjusted soas to produce an electric switch signal when a reference master radius Ris measured. Simultaneously with the setting of the generation point forobtaining a finished dimension, the generation point of a fine feedsignal which lies slightly short of the operation point of the sizingsignal is also set by taking a finish allowance into consideration. Whenit is required to size other values than the reference master radius Rthe supporter means 4 has only to be moved by a distance correspondingto a change in radius to produce a sizing signal when the feeler 3 andthe supporter means come to the predetermined position i.e., the samerelative positions as the master setting, since the feeler 3 is movedthrough contact with the workpiece W by a distance corresponding to thechange in radius of the workpiece W. Assuming that-the radius of thefinished workpiece is R (which is equal to R plus Ar), predeterminedinput pulses are applied to the pulse motor 13 so as to rotate thedilferential nut 7 and thus move the supporter means 4 a distancecorresponding to Ar. When the workpiece W is ground by the grindingwheel on the wheel slide into a radius with a finish allowance, theSchmitt circuit which responds to the displacement detector A produces afine feed signal to reduce the feed rate of the wheel slide toward theworkpiece W. Upon further reduction of the workpiece radius to therequired value R the sizing signal is produced to stop the feed motionof the wheel slide. Thus, the need for effecting a master setting eachtime the diameter of the workpiece is varied is eliminated, and one hasonly to apply to the pulse motor 13 input pulses corresponding to achange in the diameter of the workpiece. The accuracy of the sizingsignal may vary depending on the accuracy of positioning of thesupporter means 4. However, since it is possible to reduce a cumulativepitch error of a precision screw to within Lu, it has been found thatthe present invention allows sizing with an accuracy in the order ofmicrons.

A second embodiment of the invention will now be explained withreference to FIGS. 2 and 3. In this embodiment of the invention, thesizing of workpieces differing from one another in diameter over a widerrange than are the case with workpieces handled by a sizing device ofthe jaw type can be effected once an initial master setting is effected.In FIGS. 2 and 3, a sizing head includes movable supporter members 67and 68 guided and supported by guide bars 63 and 64 and supporting apair of feelers 61 and 62, respectively, which contact a workpiece W atpositions on the workpiece diametrically opposed to each other. Onefeeler 62 is supported by a cross spring '69 for pivotal displacement.Operably connected at one end of the feeler 62 is a displacementdetector A which detects the displacement of the feeler 62 relative tothe supporter member 68 which mounts the feeler 62. A threaded rod 70extending through the supporter members 67 and '68 and journalled by thesizing head is formed with a right-hand threaded portion R and aleft-hand threaded portion 70L which threadably engage nuts 71 and 72,respectively, which are fixed to the supporter members 67 and 68respectively. The threaded rod 70 is connected to a rotary shaft 78 of apulse motor 79 through the agency of a gear 73 mounted at one end of thethreaded rod 70 and in meshing engagement with a gear train consistingof gears 75, 76 and 77 mounted on an intermediate shaft 74. The gears 73and 76 are compound gears and a spring is mounted between the componentmembers of each compound gear so as to eliminate backlash between thegears in meshing engagement with each other. The pulse motor 79 is fixedto the sizing head 60. When a pulse signal is applied to the pulse motor79, the pulse motor rotates the threaded rod 70 through an angleproportional to the number of pulses of the signal applied thereto so asto move said pair of feelers 61 and 62 toward or away from each other.The sizing head 60 is pivotally mounted by a pin 82 on a bracket 81secured to a main body 80. The main body is connected to a suitablereciprocating mechanism as is the case with the first embodiment of theinvention.

In the sizing device of the type described, the movable supportermembers 67 and '68 mounting the pair of feelers 61 and 62 are moved adistance corresponding to the amount of change of the workpiece diameterin the radial direction of the workpiece W, whereby the sizing signal isgenerated when the pivotable feeler 62 comes to the predeterminedposition with respect to the displacement detector A, regardless of theworkpiece diameter change. This embodiment of the invention operates inthe same manner as the first embodiment. However, since the feelers 61and 62 are moved radially of the workpiece, they never interfere withthe operation of a grinding wheel, no matter in what positions thefeelers may be disposed. This allows a great increase in the range ofpossible sizing. Moreover, sizing can be elfected in the secondembodiment over a wide range once a master setting is first effected.

In the second embodiment of the invention, it is essential to accuratelydetermine the distance between the pair of feelers after they are movedrelative to each other, in order to vary the point of operation of thesizing signal. In addition, it is essential to have the movablesupporter members accurately guided in sliding motion in the sizing headin order to prevent the forward ends of the feelers from being deflectedradially of the workpiece and displaced. A third embodiment shown inFIGS. 4 and 5 include guide means of special construction for the feelersupporters and means for preventing dust collection mounted in thesliding guide portion.

In FIG. 4, a sizing head 83 is pivotally mounted by a pin 87 on areciprocable bracket 86 connected to a pilot bar 84 and a piston rod 85of a hydraulic reciprocating power motor (not shown). Mounted at thelower end of the sizing head 83 is a plunger 89 which is urged by aspring 88 to bear against the front surface of the bracket 86 so as tomaintain the sizing head balanced at the pivoting pin 87. A projection90 adjustably secured to the sizing head 83 which has an enlargement atthe left hand end regulates the range of pivotable movement of thesizing head 83 in cooperation with a stop 91 fixed on the bracket 86.

Mounted in the upper and lower portions of the sizing head 83 on itsfront surface are jaws 92 and 93 between which two pilot bars 94 and 95extend, the opposite ends of the pilot bars 94 and 95 being secured bynuts 96. A feed rod 97 formed with a right-hand threaded portion 97R anda left-hand threaded portion 97L thereon is rotatably mounted in .aposition corresponding to the apex of a triangle having its base on aline connecting the center of axis of the pilot bar 94 with the centerof axis of the pilot bar 95. The feed rod 97 is connected through theagency of a gear 98 mounted at its upper end and meshing with a geartrain consisting of gears 99, 101, 102, 103 and 104 to a rotary shaft106 of a pulse motor fixed to the sizing head 83. In order to eliminatethe backlash of the gears, springs 107 are mounted between the componentmembers of each of the compound gears 98, 101 and 103 which are inmeshing engagement with single gears, 99, 102 and 104, respectively.Supporter members and 111 mounting feelers 108 and 109 respectively, areslidably guided by the pilot bars 94 and 95, respectively. The supportermembers 110 and 111 are formed with openings for the pilot bars 94 and95 and the feed rod 97 to extend therethrough.

A downwardly directed cylindrical extension 110a is formed integrallywith the supporter member 110, and guide bushes 112 and 113 are fittedat the upper end and the lower end, respectively, in the bore 11% of thesupporter member 110 and the cylindrical extension 110a. The guidebushes 112 and 113 are snugly and intimately fitted over the guide bar95 for sliding motion so as to thereby guide the supporter member 110 inits reciprocating motion. An upwardly directed cylindrical extension111a is formed integrally with the supporter member 111, and guidebushes 114 and 115 are fitted at the upper end and the lower end,respectively, in the bore 111b of the supporter member 111 and thecylindrical extension 111a. The guide bushes 114 and 115 are snugly andintimately fitted over the guide bar 96 for sliding motion so as tothereby guide the supporter member 96 in its reciprocating motion. Theopenings formed in the supporter members 110 and 111 for the feed rod 97to extend therethrough mount thereon internally threaded members 116 and117 which threadably engage the righthand threaded portion 97R andleft-hand threaded portion 97L of the feed rod 97, respectively. Each ofthe internally threaded members 116 and 117 consists of a set of twonuts of the circulating ball type.

The two nuts are rendered preloaded through adjustment of the thicknessof spacing collars 130 interposed therebetween to thereby eliminatebacklash.

A feeler 108 is adjustably mounted by dovetail engagement on the uppersupporter member 110, while a block 119 pivotally mounting a feeler 109and including a builtin displacement detector 118 is adjustably mountedby dovetail engagement on the lower supporter member 111. A bellows 120made of rubber or like material is clamped at its lower end to theperiphery of the upper end of the supporter member 110 and at its upperend to the peripheral edge of the jaw 92. Similarly, a bellows 121 isclamped at its opposite ends to the periphery of the lower end of thesupporter member 111 and the peripheral edge of the jaw 93. A bellows122 is clamped at its opposite ends to the lower end of the supportermember 110 and the upper end of the supporter member 111. The provisionof bellows 120, 121 and 122 is conducive to preventing grinding wheelparticles and coolant from adhering to the pilot bars and the feed rodby covering and enclosing the same.

The supporter members 110 and 111 carrying the feelers 108 and 109,respectively, as aforementioned are respectively fitted over theparallel pilot bars 94 and 95 and guided thereby through nearly theentire length. This arrangement eliminates or minimizes the deflectionof the feelers 108 and 109 radially of the workpiece when the feelerstend to be spreaded radially of the workpiece in coming into contactwith each other. The supporter members 110 and 111 guided by the pilotbars 94 and 95, respectively, threadably engage the feed rod 97 atpositions spaced apart from the center axes of the pilot bars 94 and 95,so that the supporter member 110 and 111 are restrained against rotationabout their axes by the pilot bars 94 and 95, and the feelers 108 and109 are restrained against lateral displacement. This arrangement offersan advantage in that, When a preset pulse signal is applied to the pulsemotor 105 to rotate the feed rod 97 through the agency of the gearing soas to thereby effect displacement of the feelers 108 and 109 up and downa desired amount and change the generation point of a sizing signal, thegeneration point will move accurately to a desired point. Also,deflection of each of the feelers can be minimized because of the factthat there is a clearance between the supporter member and the pilot barand the feelers are guided for nearly the entire length of the pilotbar. This is conducive to the elimination of sizing errors. Advantagesof the sizing device of the third embodiment of the invention aresummarized as follows: The sliding portions of the supporter members arecovered by bellows or other flexible protective members, so that theinvasion of coolant and grinding wheel particles into the slidingportions can be prevented during grinding operations. The inner spacescovered by the protective members maintain communication with oneanother, so that the relative sliding motion of the supporter membersdoes not cause movement of air between the inner spaces and atmosphere.Thus, no dust floating in the atmosphere will be drawn by suction intothe sliding portions. The protection provided to the sliding portionspermits the sizing device of this invention to effect sizing at highprecision for a prolonged period of time.

As aforementioned, the sizing device according to this invention asexemplified in the various embodiments described permits sizing at highprecision and over a wide range. This advantage imparts increasedversatility to this sizing device in performing grinding operations byusing this sizing device. This sizing device is particularly useful ingrinding workpieces having diverse diameters.

Application of the sizing device according to this invention to agrinding operation of the numerical control type will be explained withreference to FIG. 8. In FIG. 8, 30 refers to a tape reader, 31 to a decoder, '32 to a register in which the value in the radius of a finishedworkpiece is preset, 33 to a comparator, 34 to a counter, 35 to aregister in which the value of the radius of a reference master is set,36 to a pulse generator, 37 and 38 to AND gates, 39 and 40m gates closedonly when initial setting is effected, and 41 to a pulse motor driveunit. The data read off by the tape reader 30 are discriminated by thedecoder 31 and only the value of the radius of a finished workpiece ispreset in the register 32. The comparator 33 compares the contents ofthe counter 34 with those of the register 32 and closes or opens one ofthe gates 37 and 38. It is required to set the value of radius (R of thereference master in the counter 34 immediately after the master settingof the sizing device is effected. An initial setting signal is appliedto the gates 39 and 40 through an input terminal T so as to close thesame. At the same time, the contents of the register 35 in which theradius of the reference master is set and those of the counter 34 arecompared and one of the gates 37 and 38 is opened. Pulses are applied tothe counter 34 from the pulse generator 36 so that the value of radius(R of the reference master may be preset in the counter 34. The pulsemotor 13 remains inoperative because no pulses are applied to the pulsemotor driving unit 41. In this way, initial presetting of the referencemaster radius (R is effected in the counter 34. Thus, the initialsetting signal is cancelled. Upon presetting of a first command value (Rin the register 32, command pulses corresponding to a change in radius(Ar=R R are applied to the pulse motor drive unit 41 by the gates 37 and39 or the gates 38 and 40 so as to drive the pulse motor 13 andaccurately move the supporter means 4 by an amount corresponding to thechange in radius (Ar). When a second command value (R is applied, thesupporter means 4 is moved by an amount corresponding to a change inradius Ar=R --R because the first command value R is stored in thecounter 34. It will be evident that the supporter means 4 is moved by anamount corresponding to a change in radius or a difference between thevalue stored in the counter 34 and the new command value applied. Theprimary coil of the differential transformer is energized by an AC powersource 42 and an output signal corresponding to the amount ofdisplacement of the movable iron core 24 is produced by the secondarycoil. After being amplified by an amplifier 43, this output signal isrectified at a synchronizing and rectifying circuit 44 so that it may betaken out as a positive or a negative voltage in accordance with thedirection of displacement of the movable iron core as shown in FIG. 9b.A jump takes place in a Schmitt circuit 45 when the voltage thusdiscriminated agrees with a given set voltage. Master setting of thegeneration point for a sizing signal (S and the generation point for afine feed signal (S of the circuit is effected beforehand. The fine feedsignal and the sizing signal are applied to a feed control circuit 46for a wheel slide 49 for reducing the rate of a feed motor 47 andshutting off the motor.

After the supporter means 4 has been moved as instructed by an inputsignal from a tape or the like, the movable iron core of thedifferential transformer is posi tioned away from the generation point.In this state, a command is given to move the wheel slide 49 forwardlyat high speed, and the feed is switched to a slow feed when a grindwheel 50 is brought into contact with the workpiece W by suitable means,so that grinding can be performed. As the grinding operation progresses,the diameter of the workpiece W is reduced and the movable iron core 24draws near the operation point. When the grinding operation hasprogressed to a point where only the finish allowance is left on theworkpiece, the fine feed signal is applied and the rate 'of feed motor47 is reduced so that precision feed may be effected. A further progressin the grinding operation results in the application of the sizingsignal, whereby the feed of the wheel slide 49 is stopped and the wheelslide is moved rearwardly at high speed after spark out of apredetermined time interval. If a new command is given as to thediameter of a workpiece to be worked on, the supporter means 4 is movedby an amount corresponding to a difference in diameter between the oldand new workpieces, so that the genera tion point with respect to thecenter of the workpiece can be displaced. It will be evident that thesizing device of the present invention can handle workpieces of anydiameter in grinding operations after an initial master setting iseffected. The invention also makes it possible to effect sizing at highprecision.

The control circuit shown in FIG. 8 can also be used in cases where aseries of values corresponding to differences between the value of thereference master and the values to be achieved on the workpiece W arestored as an input signal on the tape. In this case, the register 35 inwhich the value of the radius of a reference master is set can beabolished. Control of pulses to be applied is effected by the counter 34and comparator 33 as well as by the gates 37 and 3-8 in such a mannerthat an input command value read off by the tape reader 30 is stored inthe register 32 and a pulse signal equal in number to said input commandvalue can only be applied to the pulse motor 13. Upon completion ofoperation, the contents of the counter 34 are reset. Resetting of thecounter 34 must be effected in order that a pulse signal equal in numberto the next input command value may be applied to the pulse motor.

While the present invention has been shown and described with referenceto preferred embodiments, it is to be understood that the invention isnot limited to the precise forms of apparatus, and that changes andmodifications may be made therein without departing from the scope andspirit of the invention. The appended claims should, therefore, beinterpreted vto cover such changes and modifications.

We claim:

1. A sizing device for effecting sizing over a wide range comprising asizing head, a feeler supported by said sizing head and maintained incontact with a workpiece and adapted to be displaced in conformity witha change in the dimension of the workpiece, a displacement detectorresponding to a relative change in the position of the feeler, a signaloutput circuit for generating an electric switch signal at thegeneration point set by said displacement detector, movable feed controlmeans for moving said feeler and said displacement detector to relativepositions which are predetermined with respect to the center of rotationof the workpiece, drive means connected to said feed control means, andcontrol means for applying a control signal for actuating said drivemeans, such sizing device being characterized in that said control meansapplies to said drive means a control signal representing saiddifference between the input command value and the value previously set.

2. A sizing device for effecting sizing over a wide range comprising asizing head, a pair of feelers supported by said sizing had maintainedin contact with a workpiece and adapted to be displaced in conformitywith a change in the dimension of a workpiece, a displacement detectorresponding to a change in the positions of the feeler, a signal outputcircuit for generating an electric switch signal at a generation pointset by said displacement detector, movable feed control means for movingsaid feelers and said displacement detector to relative positions whichare predetermined with respect to the center of rotation of theworkpiece, a pulse motor connected to said feed control means, andcontrol means for applying a pulse signal to said pulse motor, suchsizing device being characterized in that said control means applies tosaid pulse motor said pulse signal corresponding in the number of pulsesto a difference between the input command value and the value previouslyset.

3. A sizing device as claimed in claim 2 in which said control meanscomprises a register for storing the value of said input command signal,a reversible counter for counting the number of pulses of said pulsesignal applied to said pulse motor, a comparator for comparing thecontents of said register and said reversible counter, and a pulsegenerator for generating said pulse signal for driving said pulse motor,characterized in that said control means effects control such that saidpulse generator generates said pulse signal corresponding in the numberof pulses to a difference between the contents of said register and thecontents of said reversible counter.

4. A sizing device for effecting sizing over a wide range comprising amain supporter connected to and supported by reciprocable feed means, asizing head supported by said supporter, supporter means operativelyconnected through a differential gear to control means mounted on saidmain supporter and mounted on said sizing head in such a manner that itis restrained against rotation about its axis, a movable feelerconcentrically supported by said supporter means, a displacementdetector contained in said supporter means, and a fine threaded rodprojecting rearwardly from the rear end of the supporter means forthreadable engagement with said differential gear.

5. A sizing device as defined in claim 4 in which said sizing head isfloatingly mounted on said main supporter by a suspension spring, saidsuspension spring mounting thereon a transducer for detecting thedeflection of the suspension spring, so that the foremost advanceposition of the main supporter can be controlled by an output signalproduced by said transducer.

6. A sizing device for effecting sizing over a wide range in which apair of feelers are maintained in contact with a workpiece at positionson said workpiece diametrically opposed to each other and supported by asizing head in such a manner that the positions of contact of saidfeelers with said workpiece can be moved a predetermined distance inconformity with a value set for sizing, said sizing head mountingtherein two vertically oriented parallel pilot bars firmly secured attheir upper and lower ends, a rotatable feed rod mounted in parallelrelation to said pilot bars, and drive means for driving a pulse motorthrough a gearing so as to rotate said feed bar through a predeterminedangle in conformity with said value set for sizing, said pilot barsmounting thereon supporter members respectively which are disposed inthe upper portion and the lower portion of the pilot bars respectivelyand guided thereby in sliding motion as they are moved by said feed rodrelative to each other, one of said supporter members fixedly supportingone of said pair of feelers and the other of said supporter memberspivotally supporting the other of said pair of feelers, said pivotallysupported feeler mounting therein a displacement detector which respondsto a change in the outer diameter of the workpiece with which saidpivotally supported feeler is maintained in contact.

7. A sizing device as claimed in claim 6 in which said upper positionedsupporter member supported and guided by one of said pilot bars isformed integrally with a downwardly directed cylindrical extensionaligned with the axis of said pilot bar and fitted over said pilot barat the upper end portion and the lower end portion of the supportermember, and said lower positioned supporter member supported and guidedby the other of said pilot bars is formed integrally with an upwardlydirected cylindrical extension aligned with the axis of said pilot barand fitted over said pilot bar at the upper end portion and the lowerend portion of the supporter member, characterized in that said pair ofsupporter members are individually guided by different pilot bars intheir sliding motion.

8. A sizing device as claimed in claim 7 in which said feed rod mountedin the sizing head for causing said supporter members mounting saidfeelers to move in sliding motion relative to said two pilot barsdisposed in parallel relation to each other for individually support andguiding said supporter members is disposed such that it is positioned atthe apex of a triangle having its base on a line connecting the centerof axis of said one pilot bar with the center of axis of said outerpilot bar.

9. A sizing device as claimed in claim 6 in which said sizing head ispivotally mounted by a pin on a bracket which can be moved inreciprocating motion by a hydraulic pressure cylinder and aspring-loaded plunger is mounted in the lower end portion of the sizinghead so that said plunger may bear against the front side of saidbracket so as to thereby balance the sizing head, and a projectiondisposed in parallel relation to said plunger and formed with anengaging surface at its forward end is attached to the sizing head, saidprojecting being adapted to engage a stop attached to the front side ofthe bracket so as to thereby control the range of pivotal motion of thesizing head.

10. A sizing device as claimed in claim 8 in which a protective cover ismounted between upper and lower jaws attached to the sizing head andsaid pair of supporter members and a protective cover is also mountedbetween the supporter members whereby sliding portions of said supportermembers can be protected.

11. A sizing device for effecting sizing over a wide range comprising asizing head, a feeler supported by said sizing head and maintained incontact with a workpiece and adapted to be displaced in conformity witha change in the dimension of the workpiece, a displacement detectorresponding to a change in the position of said feeler, a signal outputcircuit for producing an electric switch signal at the generation pointset by said displacement detector, and means responding to a controlsignal for sizing to automatically move said feeler and saiddisplacement detector to relative posiitons which are predetermined withrespect to the center of rotation of the workpiece, said control signalrepresenting a difference between the input command value and the valuepreviously set.

12. A sizing device for eifecting sizing over a wide range comprising asizing head, a feeler supported by said sizing head and maintained incontact with a workpiece and adapted to be displaced in conformity witha change in the dimension of the workpiece, a displacement detectorresponding to a relative change in the position of said feeler, a signaloutput circuit for generating an electric switch signal at thegeneration point set by said displacement detector, means forautomatically moving said feeler and said displacement detector torelative positions which are predetermined with respect to the center ofrotation of 12 the workpiece, and control means for applying a controlsignal for actuating said moving means, said control signal representinga difference between the input command value and the value previouslyset.

References Cited UNITED STATES PATENTS 2,603,043 7/1952 Bontemps 51165LESTER M. SWINGLE, Primary Examiner

